1990 Acura Legend, location of main relay for fuel pump

Engines need 3 things to run-spark, compression and fuel/air. Check the simplest things first. When you turn the key and the warning lights come on, does the check engine light come on? It should turn off in 6 seconds, if everything's ok. I Check the air filter, make sure it isn't plugged up. Take off the oil fill cap, and look in. I believe you can see the rocker/cam, use a flashlight. Have someone crank the engine with the key, see if the cam turns, rocker moves. If not, broken timing belt. Next remove an igniter, put a plug in it, have it plugged in and hold the plug near a ground. Have it cranked, check for spark. If no spark, it needs more professional diagnostics. If yes, Fuel is left. If you sit in the drivers seat, windows up and quiet, turn the key to run, all the warning lights come on. The fuel pump runs for 2 seconds, a low hum from the back. You can usually here it if it is quiet around you. (Just because it makes noise, doesn't mean it's good.) Your car also has a main relay that powers the fuel pump, a common failure. Last thing to try is starting fluid sprayed into the throttle, throttle open 1/2 way, while someone cranks.
One of these should lead you to the failure. Note: the main relay is powered by the ignition system, except for that initial 2 seconds. So if there is no spark, the fuel pump won't work either.

Is the check engine light on?

How old is the battery?

Main relay costs about $80. It is buried deep under the dash, hard to access and usually labor is about 1 hour to replace at a shop.

It is your main relay. Go to Youtube and search acura legend main relay. The main relay is located by your feet above the steering column. The solder point in the relay are weak due to temperature in the car while sitting and the outside temp is high. Also do a google search. several schematics on location. I would tap mine while turning the key and it would fire right up. Best solution is to remove and resolder the joints that are bad. Visually you will know.

Tim D.

sounds like your pgmfi main relay has gone bad,pretty common on this car.it is located above the drivers knee bolster panel. 1"x1"x3" retangular box single plug

SOUNDS LIKE A PGMFI MAIN RELAY IS BAD, PRETTY COMMON ON YOUR CAR. LOCATED UNDER DRIVERS DASH AREA. YOU CAN GET AT ANY ACURA DEALER(VERY INEXPENSIVE SO I RECOMMEND TO GO DEALER ONLY ON THIS PART)

Your starting problem may be a clogged filter or a bad fuel pump. You are not having problems with the engine cranking I assume.

Take off the hose to the throttle body and look for any obstructions. This has been know to cause performance issues similar to those described

HI...
The common cause of the problem that you related.
Is the FUEL PUMP RELAY " Called MAIN RELAY.
Is located : left side under the dash.
Is a BIG relay gray colour. with a connector of 7 or 8 wires.
I recomend replace the relay.

And letme know if you solve your problem.

I hope this information work on your problem.
Thank you for use fixya.